1. Field of the Invention
The present invention relates to a bracket mounting structure for elastically supporting a center bearing provided in a middle portion of a propeller shaft in a motor vehicle to a vehicle body member.
2. Description of the Related Art
A conventional bracket mounting structure includes, for example, structures disclosed in Japanese Utility Model Application Publication No. 7-39697 and Japanese Utility Model No. 2589855. Next, a description will be given of a basic structure of the conventional bracket mounting structure mentioned above with reference to the accompanying drawings.
FIG. 2 is a partly cut-out front elevational view showing one example of a conventional bracket mounting structure which includes a propeller shaft and a center bearing.
A propeller shaft passing under a lower surface of a floor in a motor vehicle is structured such that a middle portion thereof is supported in a rotating manner to a vehicle body member, for example, a cross member via a center bearing and a bracket. As shown in FIG. 2, a center bearing 05 is held within a circular arc portion 01A of a bracket 01 via an outer ring O2, an annular vibration proof rubber 03 and an inner ring 04. A middle portion of a propeller shaft 06 is supported in a rotating manner, by the center bearing 05. Further, the bracket 01 is structured such that plate portions 01B extending rightward and leftward from the circular arc portion 01A are respectively mounted to a cross member 010 of a vehicle body by bolts 07, nuts 08 and washers 09.
FIG. 3 is an enlarged view of the mounting portion of the bracket 01, showing a state of mounting only the mounting portion to the bracket 01 supporting the center bearing 05 while omitting the bolts 07, the nuts 08, the washers 09, and the cross member 010 shown in FIG. 2. A description will be given of the mounting structure of the bracket 01 with reference to both of FIGS. 2 and 3.
First, a cylindrical bush collar 012 having a flange at an upper end is fitted to the bolt 07 mentioned above. The bush collar 012 is fixed to the cross member 010 of the vehicle body by the bolt 07 and the nut 08. A pair of upper and lower rubber bushes 013 and 014 are fitted to an outer periphery of the bush collar 012 so as to grip the bracket 01 there-between, for the purpose of preventing a vibration of the propeller shaft 06 from being transmitted to the cross member 010. Washers 015 and 016 are respectively arranged in an upper end of the upper rubber bush 013 and a lower end of the lower rubber bush 014. A rubber-like material is also partly baked on an upper surface of washer 015 and a lower surface of washer 016. Washers 015 and 016 are surrounded by the rubber bushes 013 and 014. Then, as mentioned above, the whole assembly is mounted to the cross member 010 by the bolt 07.
In this case, at a time of mounting the center bearing 05 to the vehicle body member such as the cross member 010 or the like, at a first stage, the bush collar 012, the rubber bushes 013 and 014, and the washers 015 and 016 are at first assembled in the bracket 01 in which the center bearing 05 is assembled, in an arrangement essentially shown in FIG. 3. At a second stage, they are mounted to the cross member 010 or the like by the bolts 07, the nuts 08 and the washers 09. However, in the arrangement shown in FIG. 3, since the rubber bushes 013 and 014 are fixed to the bush collar 012 only with a fastening dimension of the rubber (that is, only an elastic force of the rubber), there is a risk that the bush collar 012 may drop out from the bracket 01 if the rubber bush 014 drops out from the bush collar 012 due to a light impact or the like during assembling and conveying.
Accordingly, on the assembly line, there is the necessity of carefully assembling while avoiding impact. Further, there is a fear of a shortage of parts. Also, a step to conform that all parts are present must be performed. Although it would be possible to fix the element together by an adhesive agent, in this case, since a degreasing step would be required before applying the adhesive agent, and the reliability of such an adhesive itself is not high, additional countermeasure would be required.